Previously, there have been numerous devices developed to retain electrical apparatus with cords and plugs; however they have, in most cases, been limited to securing the plug only as a method of retention. U.S. Pat. No. 3,067,402 issued to Thaw teaches such an arrangement with a separate attachment fastened with a screw to secure an electrical plug in a female opening. Further, Caldwell, in U.S. Pat. No. 3,811,104, discloses a separate bracket attached to the wall plate screw that retains the back side of the plug. U.S. Pat. No. 3,656,083 issued to Brook provides for a rotating cover with an oval opening that, when rotatably positioned, retains the plug in place by restricting the corners of the plug. Likewise, Wasserman, in U.S. Pat. No. 3,955,870, utilizes a rotating cover to enclose the plug. U.S. Pat. No. 3,281,758, issued to Appleton, uses a mechanical locking device to retain the edges of a nonstandard plug when inserted into the receptacle and an external locking device. Other methods have been utilized to attempt to solve the problem: Boatwright, U.S. Pat. No. 3,749,815, and Kehaut, U.S. Pat. No. 3,972,579, both teach a method of retaining a cord; however in both cases, the device is a rubber grommet which is not primarily intended for stress relief or retention other than mere isolation from a round hole. This approach does not supply the cord-retaining properties of the present invention. Also, both of the disclosures are used for flush boxes with the plug inside being virtually unsupported. Further, there are no provisions for a quick release or changing of cords.
For background purposes and as indicative of the art to which the invention relates, reference may be made to U.S. Pat. No. 4,040,698 issued to Ortiz and U.S. Pat. No. 3,345,600 issued to Scherer.